A voice service includes an active interval for transmitting voice data actually and a silent interval in which voice data to be transmitted is not generated.
A method of allocating a radio source per scheduling type according to a related art is explained as follows.
FIG. 1 is a diagram for a radio resource allocating method of an unsolicited grant service (hereinafter abbreviated USG) according to a related art.
The USG supports such a real-time traffic as a voice and also allocates a radio resource of a fixed size to a mobile station by each predetermined period. Referring to FIG. 1, a mobile station transmits voice packets in an active interval using an allocated radio resource of a fixed size. In a silent interval, the mobile station transmits a silence insertion descriptor (hereinafter abbreviated ‘SID’) using a portion of the allocated radio resource of the fixed size. Since a mobile station is unable to recognize whether a connection between the mobile station and a base station is maintained unless transmitting data to the base station, the SID packets are dummy data transmitted to the base station by the mobile station to maintain the connection between the mobile station and the base station. Hence, since there exists a considerable amount of the radio resource unused in the silent interval, the radio resource is considerably wasted.
FIG. 2 is a diagram for a method of a first radio resource allocating method for an extended-real-time polling service (hereinafter named ‘ertPS’) according to a related art.
The ertPS supports a real-time traffic supporting a variable bit rate like VoIP (voice over internet protocol) that supports silence deletion.
Referring to FIG. 2, a base station allocates a radio resource of a size requested by a mobile station to a mobile station by determined periods. The mobile station then transmits voice packets using the allocated radio resource. In a silent interval, the base station allocates a radio resource of a size requested by the mobile station by periods. The mobile station transmits SID packet and a bandwidth request header (BR header) or a grant management header using the allocated resource of a changed size.
The mobile station requests to allocate a radio resource of a size, which is different from that of a current period, from a next period through the bandwidth request header or the grant management header.
In FIG. 2, by a first period of the silent interval, the mobile station receives an allocation of a radio resource of the same size in the active interval and then transmits SID packet and a bandwidth request header or a grant management header via a portion of the allocated radio resource. Yet, the rest of the allocated radio resource is wasted. By a second period of the silent interval, the mobile station receives an allocation of a radio resource of a size smaller than that of the former radio resource allocated by the first period of the silent interval and then transmits a bandwidth request header or a grant management header through a portion of the allocated radio resource. Yet, the rest of the allocated radio resource is wasted. By a sixth period of the silent interval, the mobile station requests a radio resource corresponding to a size of a voice packet via a bandwidth request header or a grant management header. Therefore, since there exists a considerable amount of unused radio resource in the silent interval, the radio resource is considerably wasted.
FIG. 3 is a diagram for a second radio resource allocating method for an extended-real-time polling service (hereinafter abbreviated ‘ertPS’) according to a related art.
Referring to FIG. 3, a base station allocates a radio resource of a size requested by a mobile station to the mobile station by determined periods. The mobile station then transmits voice packets using the allocated radio resource.
In a silent interval, the base station allocates a radio resource of a size requested by the mobile station. In doing so, the base station is unable to receive data via the allocated radio resource, the base station stops allocating the radio resource. In particular, in FIG. 3, by a fourth period of the silent interval, the base station is unable to receive data via the allocated radio resource and does not allocate the radio resource since then.
The mobile station transmits SID packet and a bandwidth header (BD header) or a grant management header using the radio resource allocated in the silent interval. If the mobile station fails in receiving the allocation of the radio resource, the mobile station requests the radio resource by a content or non-content based scheme on an uplink control channel. In this case, the uplink control channel includes a bandwidth request channel and a fast feedback channel.
According to the second radio resource allocating method for the ertPS, an uplink control channel has a latency problem due to a transmit period or a contention-based scheme and a signaling overhead may increase.
A resource requesting method in a wireless communication system can be categorized into a 5-step scheme and a 3-step scheme which is a fast access scheme.
First of all, according to the 3-step scheme, a mobile station transmits a bandwidth request indicator and a quick access message to a base station. In this case, the quick access message can include a mobile station ID, a requested resource size, a QoS ID and the like. Having received the bandwidth request indicator and the quick access message from the mobile station, the base station allocates an uplink resource to the mobile station. Subsequently, the mobile station transmits data via the allocated resource. In doing so, the mobile station is able to an additional uplink bandwidth request information.
Secondly, the 5-step scheme is usable independently from the 3-step scheme or is usable as substitutive scheme for the 3-step scheme.
According to the 5-step scheme, if a mobile station transmits a bandwidth request indicator to a base station, the base station allocates an uplink resource for transmitting a bandwidth request message (BW-REQ message) to the mobile station. If the mobile station sends a bandwidth request message via the allocated resource, the base station allocates an uplink resource to the mobile station. Subsequently, the mobile station transmits data via the allocated resource. In doing so, the mobile station is able to additional uplink bandwidth request information.
Since a size of a quick access message or a bandwidth request message is limited, a quantity or size of information carried by the quick access message or the bandwidth request message is limitative. However, as information, which should be transmitted by the mobile station in a process for requesting an uplink resource, differs in accordance with property of data the mobile station intends to transmit, it is impossible for all information, which is required for requesting an uplink resource for transmitting data of all properties, to be included in the quick access message or the bandwidth request message.